Since I haven't posted Japanese words frequently enough to claim to have a word of the day, 挫折（ざせつ） is my word of the week. Or one of my words of the week. It is not a particularly positive word, so I'll have to find a nice positive word to accompany it.
挫折 is a noun and a verb. It means a breakdown; a setback; a frustration.
The other word is 積極的（せっきょくてき）which is a na-adjective. It means positive; active; aggressive; enterprising; enthusiastic. A good personality trait.
積極的に考えるようにします。 "I will try to think positively."
make an effort to ～
I'll make an effort to speak in Japanese.